Volume 4, Book 53, Number 355:
Narrated Abu Musa Al-Ashari:
A bedouin asked the Prophet, “A man may fight for the sake of booty, and another may fight so
that he may be mentioned by the people, and a third may fight to show his position (i.e. bravery);
which of these regarded as fighting in Allah’s Cause?” The Prophet said, “He who fights so that Allah’s
Word (i.e. Islam) should be superior, fights for Allah’s Cause.”